Conditions are variable across the Purcells. In isolated areas, a persistent weak layer may still be reactive to human triggers. Take the time to investigate your local snowpack.
Weather Forecast
A cool, dry spell is starting. Expect light northerly winds, a mix of sun and valley cloud and cool temperatures for the foreseeable future.For more details check out https://avalanche.ca/weather.
Avalanche Summary
On Wednesday, two avalanches were triggered by skiers in the Golden backcountry. The first was a size 2 wind slab which occurred on a northwest aspect at about 2400 m. It was up to 50 cm in depth and ran approximately 600 m. The second was a size 2.5 wind slab at ridgetop. This also occurred on a NW aspect at 2400 m elevation. This avalanche stepped down to a deeper layer lower down in the start zone, likely the early December interface. On Thursday, a large settlement was felt in a flat meadow in the Invermere backcountry. This occurred at 2200 m in a below treeline terrain feature and the failure layer is unknown. Since then, several small loose dry avalanches and one size 1.5 wind slab have been observed.
Snowpack Summary
20-30 cm of low-density snow typically overlies a well-settled mid and lower snowpack. Surface hoar and near-surface facets may be mingled with a few cm dry new snow. Wind slabs may be found in the lee of ridges and ribs. Between 40 and 100 cm below the surface you'll probably find a weak layer which was buried in early December. At and below treeline, this layer mainly consists of large surface hoar. At higher elevations, this layer consists of a sun crust, facets, and/or small surface hoar. This layer is still reactive in some snowpack tests and has produced at least one human-triggered avalanche in the last week. The layer is creating a low probability, high consequence type of problem, especially in the north of the region. Below this layer, the snowpack is thought to be generally strong and well-settled.
Problems
Wind Slabs
Wind Slab avalanches are the release of a cohesive layer of snow (a slab) formed by the wind. Wind typically transports snow from the upwind sides of terrain features and deposits snow on the downwind side. Wind slabs are often smooth and rounded and sometimes sound hollow, and can range from soft to hard. Wind slabs that form over a persistent weak layer (surface hoar, depth hoar, or near-surface facets) may be termed Persistent Slabs or may develop into Persistent Slabs.
Persistent Slabs
Persistent Slab avalanches are the release of a cohesive layer of snow (a slab) in the middle to upper snowpack, when the bond to an underlying persistent weak layer breaks. Persistent layers include: surface hoar, depth hoar, near-surface facets, or faceted snow. Persistent weak layers can continue to produce avalanches for days, weeks or even months, making them especially dangerous and tricky. As additional snow and wind events build a thicker slab on top of the persistent weak layer, this avalanche problem may develop into a Deep Persistent Slab.